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Title page for ETD etd-07102008-091533

Type of Document

Dissertation

Author

Lu, Xiong

URN

etd-07102008-091533

Title

Studies of Si/SiO2 heterostructures using second harmonic generation

Degree

PhD

Department

Physics

Advisory Committee

Advisor Name

Title

Norman H. Tolk

Committee Chair

Jimmy L. Davidson

Committee Member

Ronald D. Schrimpf

Committee Member

Royal Albridge

Committee Member

Sait Umar

Committee Member

Keywords

si/sio2

second harmonic generation

nonlinear susceptibility

semiconductor

SOI

Date of Defense

2008-06-12

Availability

unrestricted

Abstract

In this thesis, we report our work on temperature dependence of second harmonic generation in Si/SiO2, which has led to an enhanced understanding of the physical processes associated with creation of the photo-induced electric field. The experimental data showed that the second- and third-order nonlinear susceptibilities increased with temperature. The data also showed that the number of filled electron trap states at the oxide surface, which is the origin of the photo-induced electric field, doesn’t change with temperature. Moreover, the temperature dependence of the trapping rate is a combination effect of electron-phonon scattering, and of the temperature dependence of the Si absorption coefficient and the SiO2 dielectric constant. We also report our recent SHG studies of silicon-on-Insulator (SOI) wafers and Si/SiO2/MgO structures, which show that the SHG is a very sensitive tool to monitor properties of the multi-layer structures.

In summary, we demonstrate that second harmonic generation is an effective, nondestructive technique for characterization of thin oxide and multi-interface structures.